*{
    margin: 0;
    padding: 0;
}
ul{
    list-style: none;
}
main{
    width: 960px;
    height: 500px;
    border-radius: 10px;
    margin: 50px auto;
}
main h4{
    height: 100px;
    line-height: 100px;
    text-align: center;
}
.tabsbox{
    width: 900px;
    height: 400px;
    margin: 0 auto;
    border: 1px solid lightsalmon;
    position: relative;
}
nav ul {
    overflow: hidden;
}
nav ul li{
    float: left;
    width: 100px;
    height: 50px;
    line-height: 50px;
    text-align: center;
    border-right: 1px solid #ccc;
    position: relative;
}
nav ul li.liactive{
    border-bottom: 2px solid #fff;
    z-index: 9;
}
#tab input{
    width: 80%;
    height: 60%;
}
nav ul li span:last-child{
    /* 控制用户能否选中文本 */
    user-select: none;
    position: absolute;
    font-size: 12px;
    top: -18px;
    right: 0;
    display: inline-block;
    height: 20px;
}
.tabadd{
    position: absolute;
    top: 0;
    right: 0;
}
.tabadd span{
    display: block;
    width: 20px;
    height: 20px;
    line-height: 20px;
    text-align: center;
    border: 1px solid #ccc;
    float: right;
    margin: 10px;
    user-select: none;
}
.tabscon{
    width: 100%;
    height: 300px;
    position: absolute;
    padding: 30px;
    top:50px;
    left: 0;
    box-sizing: border-box;
    border-top: 1px solid #ccc;
}
.tabscon section,.tabscon section.conactive{
    width: 100%;
    height: 100%;
    display: none;
}
.tabscon section.conactive{
    display: block;
}